Road Construction: Materials and Methods

This study was conducted to assess the effect of traditional and industrial waste materials approved for road construction on the surrounding environment and adjacent water bodies. A list of construction and maintenance materials was selected for this investigation based on their wide use and information extracted from their material safety datasheets. A toxicity-based approach was employed as an effective way of screening the toxicity of the selected materials. Toxicity tests using algae and Daphnia were conducted to determine the level of toxicity in water elutriates prepared from the selected materials that emulate storm water runoff. Many of the tested construction materials proved to be toxic to the test organisms. Heavy metals such as aluminum, arsenic, lead, and mercury and some hydrocarbon compounds present in test elutriates appeared to be major causes of toxicity. However, measured toxicity was significantly reduced or eliminated when elutriates were allowed to be in contact with selected soils. Under actual field conditions, mechanisms other than soil sorption such as volatilization, photolysis, and biodegradation are believed to further reduce the toxicity of storm water runoff.